Bartering is based on a simple concept: Two individuals negotiate to determine the relative value of their goods and services and offer them to one another in an even exchange. It is the oldest form of commerce, dating back to at time before hard currency even existed. (Learn more about how bartering evolved, read The History of Money: From Barter To Banknotes.)
As Orlove noted, barter may occur in commercial economies, usually during periods of monetary crisis. During such a crisis, currency may be in short supply, or highly devalued through hyperinflation. In such cases, money ceases to be the universal medium of exchange or standard of value. Money may be in such short supply that it becomes an item of barter itself rather than the means of exchange. Barter may also occur when people cannot afford to keep money (as when hyperinflation quickly devalues it).[15]
Other anthropologists have questioned whether barter is typically between "total" strangers, a form of barter known as "silent trade". Silent trade, also called silent barter, dumb barter ("dumb" here used in its old meaning of "mute"), or depot trade, is a method by which traders who cannot speak each other's language can trade without talking. However, Benjamin Orlove has shown that while barter occurs through "silent trade" (between strangers), it also occurs in commercial markets as well. "Because barter is a difficult way of conducting trade, it will occur only where there are strong institutional constraints on the use of money or where the barter symbolically denotes a special social relationship and is used in well-defined conditions. To sum up, multipurpose money in markets is like lubrication for machines - necessary for the most efficient function, but not necessary for the existence of the market itself."[12]
In his analysis of barter between coastal and inland villages in the Trobriand Islands, Keith Hart highlighted the difference between highly ceremonial gift exchange between community leaders, and the barter that occurs between individual households. The haggling that takes place between strangers is possible because of the larger temporary political order established by the gift exchanges of leaders. From this he concludes that barter is "an atomized interaction predicated upon the presence of society" (i.e. that social order established by gift exchange), and not typical between complete strangers.[13]
The same thing holds true of all other possessions; for barter, in general, had its original beginning in nature, some men having a surplus, others too little of what was necessary for them: hence it is evident, that the selling provisions for money is not according to the natural use of things; for they were obliged to use barter for those things which they wanted; but it is plain that barter could have no place in the first, that is to say, in family society; but must have begun when the number of those who composed the community was enlarged: for the first of these had all things in common; but when they came to be separated they were obliged to exchange with each other many different things which both parties wanted.
Since the 1830s, direct barter in western market economies has been aided by exchanges which frequently utilize alternative currencies based on the labor theory of value, and designed to prevent profit taking by intermediators. Examples include the Owenite socialists, the Cincinnati Time store, and more recently Ithaca HOURS (Time banking) and the LETS system.
Communities of Iroquois Native Americans, for instance, stockpiled their goods in longhouses. Female councils then allocated the goods, explains Graeber. Other indigenous communities relied on “gift economies,” which went something like this: If you were a baker who needed meat, you didn’t offer your bagels for the butcher’s steaks. Instead, you got your wife to hint to the butcher’s wife that you two were low on iron, and she’d say something like “Oh really? Have a hamburger, we’ve got plenty!” Down the line, the butcher might want a birthday cake, or help moving to a new apartment, and you’d help him out.
Michael Linton originated the term "local exchange trading system" (LETS) in 1983 and for a time ran the Comox Valley LETSystems in Courtenay, British Columbia.[26] LETS networks use interest-free local credit so direct swaps do not need to be made. For instance, a member may earn credit by doing childcare for one person and spend it later on carpentry with another person in the same network. In LETS, unlike other local currencies, no scrip is issued, but rather transactions are recorded in a central location open to all members. As credit is issued by the network members, for the benefit of the members themselves, LETS are considered mutual credit systems.

When barter has appeared, it wasn’t as part of a purely barter economy, and money didn’t emerge from it—rather, it emerged from money. After Rome fell, for instance, Europeans used barter as a substitute for the Roman currency people had gotten used to. “In most of the cases we know about, [barter] takes place between people who are familiar with the use of money, but for one reason or another, don’t have a lot of it around,” explains David Graeber, an anthropology professor at the London School of Economics.

Check online swap markets and online auctions that have a bartering component such as Craigslist.com (check under "For Sale" for the Bartering category), Swapace.com, SwapThing.com, Barterquest.com, U-Exchange.com, Trashbank.com and Ourswaps.com. Check for local bartering clubs. Your local Chamber of Commerce may be able to provide you with information on similar clubs in your area.

It is estimated that over 450,000 businesses in the United States were involved in barter exchange activities in 2010. There are approximately 400 commercial and corporate barter companies serving all parts of the world. There are many opportunities for entrepreneurs to start a barter exchange. Several major cities in the U.S. and Canada do not currently have a local barter exchange. There are two industry groups in the United States, the National Association of Trade Exchanges (NATE) and the International Reciprocal Trade Association (IRTA). Both offer training and promote high ethical standards among their members. Moreover, each has created its own currency through which its member barter companies can trade. NATE's currency is the known as the BANC and IRTA's currency is called Universal Currency (UC).[28]

While one-to-one bartering is practiced between individuals and businesses on an informal basis, organized barter exchanges have developed to conduct third party bartering which helps overcome some of the limitations of barter. A barter exchange operates as a broker and bank in which each participating member has an account that is debited when purchases are made, and credited when sales are made.